i5 



should be noted that the lowest pair of supra-dichotomial constrictions is usually even (Figs. 

 71, 73 c), that is, they are not situated at markedly unequal distances above the dichotomy. 



Sonder and J. G. Agardh (loc. cit.) describe what they believe to be the sporangia of 

 Cklorodesmis, situated in the apices of the free filaments. Madame Weber van Bosse noticed 

 in her Dongala material, when freshly gathered, the escape of roundish, apparently non-motile, 

 spores from the apex of one of the filaments. 



We have seen 110 specimen of Vaucheria fastigiata C. A. Agardh (Syst. Algar. 1824 

 p. 176) which was collected by Gaudichaud at the Marianne Islands and referred by J. G. 

 Agardh (Till Alg. Syst. V. 1887, p. 51) to Cklorodesmis comosa with some slight reservation. 

 Should J. G. Agardh's opinion be be confirmed, the specific name comosa will have to give 

 way and the present species must be called Cklorodesmis fastigiata. J. G. Agardh states that 

 Gaudichaud's specimen is not in the best condition, as might well be expected if the plant 

 really be identical with C. comosa. 



Cklorodesmis comosa Mazé et Schramm (Algues de la Guadeloupe, Edit. II. 1870 — 79, 

 p. 98) was collected at Guadeloupe ("Point a pitre, Het a Fajou ; fragments de madrepores 

 a la lame ; 5 Avril 1868"), and was issued in Mazé's exsiccatae as n°. 338. It occurs, says 



Mazé (loc. cit.) "a petite distance du rivage, eaux troubles très-remuées Colo- 



ration : vert brunatre dans 1'eau". 



The tufts are 20 cm. long; the filaments are pale green or hyaline, 80 — 150^ thick, 

 very remotely dichotomously branched, without constrictions at the dichotomies, thin-walled and 

 collapsed. The plant has been referred by Murray and Boodle (loc. cit.) to Vauckeria, but is 

 in our opinion an undescribed species of Derbesia. Some of the filaments in Mazé's specimens 

 bear numerous lateral sessile sporangia, solitary and spaced out at intervals of 400 — 700 ij.. 

 These sporangia are apparently globose and have a diameter of 1 20 p., which is also the 

 diameter of the filament which bears them. But the filaments and sporangia are so irretrievably 

 crushed in these dry old specimens as to render further investigation impossible to us. 



Avrainvillea comosa Börgesen in Vidensk. Meddel. naturh. Foren. Köbnhavn. 1908, 

 p. 28, fig. 1, from the Danish West Indies, is in our opinion not Cklorodesmis comosa Bail. & 

 Harv., but differs from that species in having having its filaments much longer, somewhat 

 thicker, very thin-walled, only slightly branched and entirely destitute of the characteristic 

 constrictions of the true C. comosa. Moreover the rhizoids figured by Dr. Börgesen (loc. cit.) 

 are long and 2 — 3 times dichotomously branched, recalling those of Udotea, and are quite 

 different from the simple rhizoids found in C. comosa Bail. & Harv.. This latter species appears 

 to be confined to the Pacific and Indian Oceans. 



Whether Dr. Börgesen's plant could possibly be conspecific with the C. comosa of Mazé & 

 Schramm (Guadeloupe: Mazé n° 338), discussed above, is a question which we are quite unable 

 to decide. The long thin-walled slightly branched filaments, destitute of constrictions, characterise 

 both plants ; and both occur in the West Indies. A comparison of alcohol-material is desirable 1 ). 



1) While these sheets are passing through the press, we hear from Dr. Börgesen, that he has deteimined the Cklorodesmis 

 comosa of Crouan and Mazé & Schramm in Ilerb. Mus. Paris to be Vaucheria dichotoma (L.) Ag. jf, and considers it to be identical 

 with his own Avrainvillea comosa from the Danish West Indies. 



